Method of atomizing a fluid composition

ABSTRACT

A method of atomizing a fluid composition is disclosed. The method includes the steps of: providing a fluid composition; atomizing the fluid composition from a nozzle of a microfluidic die, wherein the atomized fluid composition comprises a plurality of droplets having a bimodal distribution, wherein the bimodal distribution comprises: 80% or greater of the total volume of the plurality of droplets is less than 10 pL; 30% or greater of the total volume of the plurality of droplets is less than 5 pL; and 30% or greater of the total volume of the plurality of droplets is from 6 pL to 10 pL.

FIELD

The present invention is directed to a method of atomizing a fluid composition, and, more particularly, to a method of atomizing a fluid composition having a bimodal distribution.

BACKGROUND

Various systems exist to deliver fluid compositions, such as perfume compositions, into the air by energized (i.e. electrically/battery powered) atomization. In addition, recent attempts have been made to deliver fluid compositions, such as perfume compositions, into the air using microfluidic delivery technology such as thermal and piezo microfluidic dies.

When using microfluidic delivery technology to deliver fluid compositions, especially when delivering the fluid compositions into the air, proper dispersion of the atomized fluid composition into the surrounding space may be important for consumer noticeably. Many variables can affect the output of the microfluidic delivery device, including viscosity of fluid, frequency of firing, temperature, etc. There is a continuing need to optimize the operating conditions and output parameters to deliver a more consistent and noticeable scent experience.

SUMMARY

“Combinations:”

A. A method of atomizing a fluid composition, the method comprising the steps of:

-   -   providing a fluid composition;     -   atomizing the fluid composition from a nozzle of a microfluidic         die, wherein the atomized fluid composition comprises a         plurality of droplets having a bimodal distribution, wherein the         bimodal distribution comprises:     -   80% or greater of the total volume of the plurality of droplets         is less than 10 pL;     -   30% or greater of the total volume of the plurality of droplets         is less than 5 pL; and     -   30% or greater of the total volume of the plurality of droplets         is from 6 pL to 10 pL.

B. The method of Paragraph A, wherein the plurality of droplets comprise:

-   -   80% or greater of the total volume of the plurality of droplets         is from 1 to 10 pL; and     -   50% or greater of the total volume of the plurality of droplets         is from 1 to 5 pL.

C. The method of Paragraph A or Paragraph B, wherein the step of atomizing the fluid composition further comprises atomizing the fluid composition at a frequency of 1000 Hz to 6000 Hz.

D. The method of Paragraph C, wherein the step of atomizing the fluid composition further comprises atomizing the fluid composition at a frequency of 2000 Hz to 4000 Hz.

E. The method of any of Paragraphs A through D, wherein the fluid composition comprises at least 60 wt. % of a perfume mixture, based on the total weight of the fluid composition.

F. The method of any of Paragraphs A through E further comprising the step of heating the composition with a thermal actuator.

G. The method of Paragraph F, wherein the step of atomizing the fluid composition further comprises atomizing the heated fluid composition from a nozzle of a microfluidic die, the microfluidic die comprising a silicon semiconductor substrate containing a plurality of heater resistors, at least one fluid chamber associated with each heater resistor, and at least one nozzle associated with each fluid chamber.

H. The method of Paragraph F, wherein the step of atomizing the fluid composition further comprises atomizing the heated fluid composition from a nozzle in a direction that is from 0 degrees to 90 degrees from the direction of action of gravity.

I. The method of Paragraph F, wherein the microfluidic die comprises a nozzle plate comprising the at least one nozzle, and wherein the nozzle plate comprises an oleophobic surface coating.

J. The method of any of Paragraphs A through I, wherein the fluid composition comprises a perfume mixture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a microfluidic cartridge with an electric circuit and microfluidic die.

FIG. 2 is a sectional view of a microfluidic cartridge.

FIG. 3 is an exploded view of an electric circuit and microfluidic die on a microfluidic cartridge.

FIG. 4 is a sectional view of a microfluidic die.

FIG. 5 is a plan view of a portion of a microfluidic die.

FIG. 6 is a perspective view of the front of a microfluidic delivery device.

FIG. 7 is a perspective view of the back of a microfluidic delivery device.

FIG. 8 is a top, plan view of a microfluidic delivery device.

FIG. 9 is a histogram of observed droplets of the Example Fluid Composition jetted from an exemplary microfluidic die using the described Video-Based Droplet Sizing Method, firing at 1000 Hz.

FIG. 10 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 9.

FIG. 11 is a histogram of observed droplets of the Example Fluid Composition jetted from an exemplary microfluidic die using the described Video-Based Droplet Sizing Method, firing at 2000 Hz.

FIG. 12 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 11.

FIG. 13 is a histogram of observed droplets of the Example Fluid Composition jetted from an exemplary microfluidic die using the described Video-Based Droplet Sizing Method, firing at 3000 Hz.

FIG. 14 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 13.

FIG. 15 is a histogram of observed droplets of the Example Fluid Composition jetted from an exemplary microfluidic die using the described Video-Based Droplet Sizing Method, firing at 4000 Hz.

FIG. 16 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 15.

FIG. 17 is a histogram of observed droplets of the Example Fluid Composition jetted from an exemplary microfluidic die using the described Video-Based Droplet Sizing Method, firing at 5000 Hz.

FIG. 18 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 17.

FIG. 19 is a histogram of observed droplets of the Example Fluid Composition jetted from an exemplary microfluidic die using the described Video-Based Droplet Sizing Method, firing at 6000 Hz.

FIG. 20 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 19.

FIG. 21 is a plot of volume fraction of drops dispensed in droplets having volume 5 pL or less, versus firing frequency.

DETAILED DESCRIPTION

While the below description describes a fluid composition, a microfluidic delivery device and a method of atomizing a fluid composition, both having various components, it is to be understood that the fluid composition, microfluidic delivery device, and method of atomizing a fluid composition are not limited to the construction and arrangement set forth in the following description or illustrated in the drawings.

The present disclosure is directed to a method of atomizing a fluid composition from a microfluidic die. The microfluidic die of the present disclosure provides an optimized dispersion of fluid composition droplets throughout a space and adjacent spaces by providing a consistent bi-modal distribution of droplets having a plurality of small droplets and a plurality of large droplets.

The microfluidic delivery device may include a housing electrically connectable with a power source, a cartridge releasably connectable with the housing. The cartridge has a reservoir for containing a fluid composition and a microfluidic die in fluid communication with the reservoir.

Microfluidic Device

With reference to FIGS. 1 and 2, a microfluidic cartridge 10 comprises an interior 12 and an exterior 14. The interior 12 of the microfluidic cartridge 10 comprises a reservoir 16 and one or more fluid channels 18 that are in fluid communication with the microfluidic die 51. The reservoir 16 may be formed from a base wall 20 or a plurality of surfaces forming a base wall 20 and one or more side walls 22. The reservoir 16 may be enclosed by a lid 24 of the microfluidic cartridge 10. The fluid channel 18 extends from reservoir 16 to the exterior 14 of the microfluidic cartridge 10 at the fluid opening. The reservoir may include an air vent. The lid 24 may be integral with the reservoir 16 or may be constructed as a separate element that is connected with the reservoir 16.

The reservoir 16 of the microfluidic cartridge 10 may contain from about 5 mL to about 50 mL of fluid composition, alternatively from about 10 mL to about 30 mL of fluid composition, alternatively from about 15 mL to about 20 mL of fluid composition. The reservoir 16 can be made of any suitable material for containing a fluid composition. Suitable materials for the containers include, but are not limited to, plastic, metal, ceramic, composite, and the like. A microfluidic cartridge may be configured to have multiple reservoirs, each containing the same or a different composition. The microfluidic delivery device may utilize one or more microfluidic cartridges, each containing a separate reservoir.

The reservoir 16 may also contain a porous material 19 such as a sponge that creates a back pressure to prevent the fluid composition from leaking from the microfluidic die when the microfluidic die is not in operation. The fluid composition may travel through the porous material and to the microfluidic die through gravity force and/or capillary force acting on the fluid composition. The porous material may comprise a metal or fabric mesh, open-cell polymer foam, or fibrous polyethylene terephthalate, polypropylene, or bi-components of fibers or porous wick, that contain multiple interconnected open cells that form fluid passages. The sponge may be made of a polyurethane or melamine foam.

With reference to FIG. 1, the exterior 14 of the microfluidic cartridge 10 is made up of two, three, or more faces. Each face is bounded by one or more edges. Two faces are connected along an edge. Each face may be flat, substantially flat, or contoured in various ways. The faces may connect to form various shapes, such as a cube, cylinder, cone, tetrahedron, triangular prism, cuboid, etc. The microfluidic cartridge may be comprised of various materials, including plastic, metal, glass, ceramic, wood, composite, and combinations thereof. Different elements of the microfluidic cartridge may be comprised of the same or different materials.

The microfluidic cartridge 10 may comprise at least a first face 26 and a second face 28 joined along an edge 30. For example, the first face 26 may be a bottom face and the second face 28 may be a side face.

In a microfluidic cartridge 10 that is substantially cube-shaped, the microfluidic cartridge 10 may include a top face, a bottom face that opposes the top face, and four side faces extending between the top and bottom faces. Each joining face may be connected along an edge. In a cylindrical-shaped microfluidic cartridge, for example, the microfluidic cartridge may include a top face, a bottom face opposing the top face, and a single curved side face extending between the top and bottom faces.

With reference to FIGS. 1-3, the fluid channel 18 of the microfluidic cartridge 10 may extend to a fluid opening that may be disposed in the second face 28 of the microfluidic cartridge 10. The microfluidic cartridge 10 may include a microfluidic die 51 disposed on the second face 28. The fluid channel 18 may open up to the microfluidic die 51 such that the fluid channel 18 is in fluid communication with the microfluidic die 51.

The primary components of a microfluidic die are a semiconductor substrate, a flow feature layer, and a nozzle plate layer. The flow feature layer and the nozzle plate layer may be formed from two separate layers or one continuous layer. The semiconductor substrate is preferably made of silicon and contains various passivation layers, conductive metal layers, resistive layers, insulative layers and protective layers deposited on a device surface thereof. Fluid ejection actuators in the semiconductor substrate generate rapid pressure impulses to eject the fluid composition from the nozzles. The rapid pressure impulses may be generated by piezoelectric device that vibrates at a high frequency (e.g., micro-mechanical actuation) or by a heater resistor that cause volatilization of a portion of a fluid composition through rapid heating cycles (e.g., micro-thermal nucleation). For thermal actuators, individual heater resistors are defined in the resistive layers and each heater resistor corresponds to a nozzle in the nozzle plate for heating and ejecting the fluid composition from the nozzle.

With reference to FIGS. 4 and 5, there is shown a simplified representation of a portion of a microfluidic die 51. The microfluidic die includes a semiconductor substrate 112 that may be a silicon semiconductor substrate 112 containing a plurality of fluid ejection actuators 114 such as piezoelectric devices or heater resistors formed on a device side 116 of the substrate 112 as shown in the simplified illustration of FIG. 5. In a microfluidic die having piezo actuators as the fluid ejection actuators 114, the piezo actuator may be disposed adjacent the nozzle such as shown in FIG. 5 or may be disposed away from the nozzles and still transmit the pressure pulse to the fluid composition to be ejected from the nozzles. Upon activation of fluid ejection actuators 114, fluid supplied through one or more fluid supply vias 118 in the semiconductor substrate 112 flows through a fluid supply channel 120 to a fluid chamber 122 in a thick film layer 124 where the fluid is caused to be ejected through nozzles 126 in a nozzle plate 128. Fluid ejection actuators are formed on the device side 116 of the semiconductor substrate 112 by well-known semiconductor manufacturing techniques. Thick film layer 124 and nozzle plate 128 may be separate layers or may be one continuous layer.

The nozzle plate 128 may include an oleophobic surface coating. The oleophobic surface coating may include polypropylene, polytetrafluoroethene, and the like.

The nozzle plate 128 may include about 4-200 nozzles 126, or about 6-120 nozzles, or about 8-64 nozzles. Each nozzle 126 may deliver about 0.5 to about 35 picoliters, or about 1 to about 20 picoliters, or about 2 to about 10 picoliters of a fluid composition per electrical firing pulse. Individual nozzles 126 may have of a diameter typically about 0.0024 inches (5-50 microns). The flow rate of fluid composition released from the microfluidic die 51 could be in the range of about 5 to about 70 mg/hour or any other suitable rate or range.

With reference to FIGS. 1 and 3, the microfluidic cartridge 10 comprises an electric circuit 52. The electric circuit 52 may be in the form of a flexible circuit, semi-flexible circuit having rigid and flexible portions, and rigid circuit boards. The electric circuit 52 may include a first end portion 54, a second end portion 56, and a central portion 58 separating the first and second end portions 54 and 56, respectively. The first end portion 54 of the electric circuit 52 may include electrical contacts 60 for connecting with the electrical contacts of the housing of a microfluidic delivery device. The second end portion 56 of the electric circuit 52 may be in electrical communication with the microfluidic die 51.

In the case of a flexible or semi-flexible electric circuit 52, the electric circuit 52 may be disposed on and span two faces of the microfluidic cartridge 10. For example, with reference to FIGS. 1 and 3, for illustrative purposes only, the first end portion 54 of the electric circuit 52 may be disposed on the first face 26 of the microfluidic cartridge 10, the second end portion 56 of the electric circuit 52 may be disposed on the second face 28 of the microfluidic cartridge 10, and the central portion 58 of the electric circuit 52 may span the first and second faces 26 and 28, respectively, of the microfluidic cartridge 10.

In the case of a rigid electric circuit 52, the electric circuit 52 may be disposed on a single face of the microfluidic cartridge 52 such that the microfluidic die 51 and the electrical contacts 60 are disposed on the same face.

With reference to FIGS. 1 and 6-8, the microfluidic cartridge 10 may also comprise one or more cartridge connectors 36 to provide mechanical connection between the microfluidic cartridge 10 and the housing. A cartridge connector 36 on the microfluidic cartridge 10 may connect with or mate with a corresponding housing connector on the housing. For example, the cartridge connectors 36 may be configured as female connectors, such as openings that are configured to mate with one or more male connectors such as projections or guideposts, on the housing. Or, the cartridge connector 36 may be configured as a male connector may include one or more projections, such as guideposts, that are configured to mate with one or more female connectors such as openings on the housing. The mechanical connection between the microfluidic cartridge and the housing may help to properly align and secure the microfluidic cartridge in the housing to provide a robust electrical connection between the microfluidic cartridge and the housing.

With reference to FIGS. 6-8, a microfluidic cartridge 10 may be configured to be releasably connectable with a housing 46 of a microfluidic delivery device 44. The housing 46 may be connected with a power source 48. The housing 46 may include a receptacle 64 having an opening 66 for receiving the microfluidic cartridge 10. The receptacle 64 may receive a portion of the microfluidic cartridge 10 or the microfluidic cartridge 10 may be completely disposed within the receptacle 64. The receptacle 64 of the housing 46 may include electrical contacts 68 that are configured to electrically connect with the electrical contacts 60 of the microfluidic cartridge 10.

The receptacle 64 may include one or more housing connectors 38 configured to be received by the one or more cartridge connectors 36 of the microfluidic cartridge 10. The housing connectors 38 may be in the form of male connectors or female connectors. For example, if the cartridge connectors 36 are configured as female connectors, the housing connectors 38 may be configured as male connectors, or vice versa. The housing connectors 38 and cartridge connectors 36 may be sized and shaped to mate with each other for a sufficient mechanical and electrical connection to occur.

The housing 46 may include a faceplate 47 disposed on a front side of the housing 46. The housing 46 may also include a fluid outlet 74 for releasing the fluid composition from the microfluidic cartridge 10 into the air. The housing 46 may include an air outlet 76 for directing air toward the dispensed fluid composition upward and/or outward into the surrounding space. The fluid outlet 74 and the air outlet 76 may be disposed in the faceplate 47.

With reference to FIGS. 1 and 8, the cartridge connectors 36 and the housing connectors 38 may be used to align, secure, and limit movement of the microfluidic cartridge 10 relative to the housing of a microfluidic delivery device 44 to establish a strong electrical connection between the microfluidic cartridge 10 and the housing. The cartridge connectors 36 and the housing connectors 38 may be designed to provide either macro or micro alignment of the microfluidic cartridge 10. Mating the cartridge connectors 36 with the housing connectors 38 may prevent movement of the microfluidic cartridge 10 relative to the housing 46 of the microfluidic delivery device 44 in the X and Y-directions.

With reference to FIG. 8, the microfluidic cartridge 10 may be spring-loaded with the housing 46 in order to provide a robust electrical connection between the microfluidic cartridge 10. The microfluidic cartridge 10 may have a release button to release the microfluidic cartridge 10 from the housing 46. Or, the microfluidic cartridge 10 may be pushed toward the housing 46 to engage and/or disengage the microfluidic cartridge 10 from the housing 46. The microfluidic cartridge 10 may engage with a fastener 102 or clip to connect the microfluidic cartridge 10 into the housing 46.

The receptacle 64 may include one or more guiderails for directing the microfluidic cartridge 10 into the receptacle 64.

The microfluidic delivery device may be configured to be compact and easily portable. In such case, the microfluidic delivery device may be battery operated. The microfluidic delivery device may be capable for use with electrical sources as 9-volt batteries, conventional dry cells such as “A”, “AA”, “AAA”, “C”, and “D” cells, button cells, watch batteries, solar cells, as well as rechargeable batteries with recharging base.

The microfluidic delivery device may include a fan for generating air flow to assist with delivering the fluid composition into the air. Any fan may be used that provides the desired air flow velocity, size, and power requirements for the microfluidic delivery device. The fan may be used to push the fluid composition further into the air and/or may be used to redirect the fluid composition in a different direction than the fluid composition is dispensed from the microfluidic die. The fan may be disposed in the interior of the housing or at least partially in the interior of the housing, or at the exterior of the housing. The fan may also be used to direct air over the microfluidic die 51 to minimize the amount of fluid composition that is deposited back onto the microfluidic die 51.

Fluid Composition

To operate satisfactorily in a microfluidic delivery system, many characteristics of a fluid composition are taken into consideration. Some factors include formulating fluid compositions with viscosities that are optimal to emit from the microfluidic delivery die, formulating fluid compositions with limited amounts or no suspended solids that would clog the microfluidic delivery die, formulating fluid compositions to be sufficiently stable to not dry and clog the microfluidic delivery member, formulating fluid compositions that are not flammable, etc. For adequate dispensing from a microfluidic die, proper atomization and effective delivery of an air freshening or malodor reducing composition may be considered in designing a fluid composition.

The fluid composition may exhibit a viscosity of less than 20 centipoise (“cps”), alternatively less than 18 cps, alternatively less than 16 cps, alternatively from about 3 cps to about 16 cps, alternatively about 4 cps to about 12 cps. The fluid composition may have a surface tension below about 35, alternatively from about 20 to about 30 dynes per centimeter. Viscosity is reported in cps, as determined using an Anton Paar Kinematic SVM 3000 series Viscometer or equivalent measurement device capable of accurately measuring expected viscosity range of fluid at room temperature. This may also be a combination of instruments such as a Bohlin CVO Rheometer System in conjunction with a high sensitivity double gap geometry.

The fluid composition may be substantially free of suspended solids or solid particles existing in a mixture wherein particulate matter is dispersed within a liquid matrix. The fluid composition may have less than 20 wt. % of suspended solids, alternatively less than 15 wt. % of suspended solids, alternatively less than 10 wt. % of suspends, alternatively less than 5 wt. % of suspended solids, alternatively less than 4 wt. % of suspended solids, alternatively less than 3 wt. % of suspended solids, alternatively less than 2 wt. % of suspended solids, alternatively less than 1 wt. % of suspended solids, alternatively less than 0.5 wt. % of suspended solids, or free of suspended solids. Suspended solids are distinguishable from dissolved solids that are characteristic of some perfume materials.

It is contemplated that the fluid composition may comprise other volatile materials in addition to or in substitution for the perfume mixture including, but not limited to, volatile dyes; compositions that function as insecticides; essential oils or materials that acts to condition, modify, or otherwise modify the environment (e.g. to assist with sleep, wake, respiratory health, and like conditions); deodorants or malodor control compositions (e.g. odor neutralizing materials such as reactive aldehydes (as disclosed in U.S. 2005/0124512), odor blocking materials, odor masking materials, or sensory modifying materials such as ionones (also disclosed in U.S. 2005/0124512)).

Perfume Mixture

The fluid composition may comprise a perfume mixture present in an amount greater than about 50%, by weight of the fluid composition, alternatively greater than about 60%, alternatively greater than about 70%, alternatively greater than about 75%, alternatively greater than about 80%, alternatively from about 50% to about 100%, alternatively from about 60% to about 100%, alternatively from about 70% to about 100%, alternatively from about 80% to about 100%, alternatively from about 90% to about 100%.

The perfume mixture may contain one or more perfume raw materials. The raw perfume materials may be selected based on the material's boiling point (“B.P.”). The B.P. referred to herein is the boiling point under normal standard pressure of 760 mm Hg. The B.P. of many perfume ingredients, at standard 760 mm Hg can be found in “Perfume and Flavor Chemicals (Aroma Chemicals),” written and published by Steffen Arctander, 1969. Where the experimentally measured boiling point of individual components is not available, the value may be estimated by the boiling point PhysChem model available from ACD/Labs (Toronto, Ontario, Canada).

The perfume mixture may have a mole-weighted average log of the octanol-water partitioning coefficient (“Clog P”) of less than about 3.5, alternatively less than about 2.9, alternatively less than about 2.5, alternatively less than about 2.0. Where the experimentally measured log P of individual components is not available, the value may be estimated by the boiling point PhysChem model available from ACD/Labs (Toronto, Ontario, Canada).

It may be useful to optimize the fluid composition and/or perfume mixture of the fluid composition for critical pressure and critical temperature. The critical pressure may be optimized for bubble-formation energetics and critical temperature for kogation propensity.

The perfume mixture may have a mol-weighted average B.P. of less than 250° C., alternatively less than 225° C., alternatively less than 200° C., alternatively less than about 150° C., or alternatively about 150° C. to about 250° C.

Alternatively, about 3 wt. % to about 25 wt. % of the perfume mixture may have a mol-weighted average B.P. of less than 200° C., alternatively about 5 wt. % to about 25 wt. % of the perfume mixture has a mol-weighted average B.P. of less than 200° C.

For purposes of the present disclosure, the perfume mixture boiling point is determined by the mole-weighted average boiling point of the individual perfume raw materials making up said perfume mixture. Where the boiling point of the individual perfume materials is not known from published experimental data, it is determined by the boiling point PhysChem model available from ACD/Labs.

Table 1 lists some non-limiting, exemplary individual perfume materials suitable for the perfume mixture.

TABLE 1 CAS Number Perfume Raw Material Name B.P.(° C.) 105-37-3 Ethyl propionate 99 110-19-0 Isobutyl acetate 116 928-96-1 Beta gamma hexenol 157 80-56-8 Alpha Pinene 157 127-91-3 Beta Pinene 166 1708-82-3 cis-hexenyl acetate 169 124-13-0 Octanal 170 40-82-6 Eucalyptol 175 141-78-6 Ethyl acetate 77

Table 2 shows an exemplary perfume mixture having a total molar weighted average B.P. (“mol-weighted average boiling point”) less than 200° C. In calculating the mole-weighted average boiling point, the boiling point of perfume raw materials that may be difficult to determine, may be neglected if they comprise less than 15% by weight of the total perfume mixture, as exemplified in Table 2.

TABLE 2 Molecular B.P. CAS Number Perfume Raw Material Name Wt. % Weight Mol % (° C.) 123-68-2 Allyl Caproate 2.50 156.2 2.6 185 140-11-4 Benzyl Acetate 3.00 150.2 3.3 214 928-96-1 Beta Gamma Hexenol 9.00 100.2 14.8 157 18479-58-8 Dihydro Myrcenol 5.00 156.3 5.3 198 39255-32-8 Ethyl 2 Methyl Pentanoate 9.00 144.2 10.3 157 77-83-8 Ethyl Methyl Phenyl Glycidate 2.00 206.2 1.6 260 7452-79-1 Ethyl-2-Methyl Butyrate 8.00 130.2 10.1 132 142-92-7 Hexyl Acetate 12.50 144.2 14.3 146 68514-75-0 Orange Phase Oil 25X1.18%-Low 10.00 mixture neglected 177 Cit. 14638 93-58-3 Methyl Benzoate 0.50 136.1 0.6 200 104-93-8 Para Cresyl Methyl Ether 0.20 122.2 0.3 176 1191-16-8 Prenyl Acetate 8.00 128.2 10.3 145 88-41-5 Verdox 3.00 198.3 2.5 223 58430-94-7 Iso Nonyl Acetate 27.30 186.3 24.1 225 TOTAL: 100.00 100.0 Mol-weighted average B.P. 176.4

Solubilizing Materials

The compositions of the present disclosure may contain one or more solubilizing materials that are liquid at 20° C., where the solubilizing materials have a Hansen hydrogen-bonding parameter of greater than 9; a Hansen polarity parameter of greater than 5; and a vapor pressure of less than 267 Pa, measured at 25° C. Without wishing to be bound by theory, it is believed that the solubilizing materials regulate evaporation of any fluid composition deposited on the surface of the thermally-activated microfluidic die, thus limiting the mass transfer rate of liquid and transition of unstable materials in fluid to solid and preventing gel formation or solidification and blocking of the nozzles.

In the context of the present disclosure, the Hansen solubility parameter is defined as the square root of the cohesive energy density delta=(E/V)^(1/2), where V is the molar volume and E is the energy of vaporization. The basis of the Hansen solubility parameter (HSP) is that the total energy of vaporization of a liquid consists of several individual parts. Hansen has defined three types of contributions to the energy of vaporization, namely: dispersive (δ_(d)), polar (δ_(p)), and hydrogen bonding (&). Each parameter, δ_(d), δ_(p), and δh, is generally measured in MPa^(0.5).

The hydrogen-bonding Hansen Solubility Parameter is based upon the hydrogen bonding cohesive energy contribution to the energy of vaporization. The polar Hansen Solubility Parameter is based upon the polar cohesive energy contribution to the energy of vaporization. The hydrogen-bonding Hansen Solubility Parameter and the polar Hansen Solubility Parameter can either be calculated or predicted using the HSPiP Software, available at the following web address https://www.hansen-solubility.com/HSPiP/. The Sphere algorithm is as described in Hansen, C. M., Hansen Solubility Parameters: A User's Handbook, CRC Press, Boca Raton Fla., 2007. The Y-MB methodology was developed by Dr Hiroshi Yamamoto of Asahi Glass Corporation.

The HSPiP Software relies on a database with a limited number of materials. If HSPiP database does not have the material of interest, the following equations can be used to calculate the Hansen solubility parameters:

Ra ²=4(δD1−δD2)²+(δP1−δP2)²+(δH1−δH2)²

RED=Ra/R0

More information on the calculations can be found at https://www.hansen-solubility.com/HSP-science/basics.php.

The compositions of the present disclosure may comprise or consist essentially of greater than 1 wt. %, or greater than 5 wt. %, or greater than 8 wt. %, or greater than 10 wt. %, or greater than 12 wt. %, or greater than 15 wt. %, or greater than 18 wt. %, or greater than 20 wt. % of a solubilizer having a Hansen hydrogen-bonding parameter of greater than 9 MPa^(0.5), a Hansen polarity parameter of greater than 5 MPa^(0.5), and a vapor pressure of less than 267 Pascals (Pa) measured at 25° C. The Hansen hydrogen-bonding parameter may be greater than 9 MPa^(0.5), or greater than 10 MPa^(0.5), or greater than 12 MPa^(0.5), or greater than 15 MPa^(0.5). The Hansen polarity parameter may be greater than 5 MPa^(0.5), or greater than 6 MPa^(0.5), or greater than 7 MPa^(0.5), or greater than 8 MPa^(0.5). The vapor pressure may be less than 267 Pa, preferably less than 137 Pa, preferably less than 67 Pa, preferably less than 34 Pa, more preferably less than 14 Pa, and more preferably less than 1.5 Pa, measured at 25° C.

A solubilizer having a Hansen hydrogen-bonding parameter of greater than 9 MPa^(0.5), a Hansen polarity parameter of greater than 5 MPa^(0.5), and a vapor pressure of less than 267 Pa measured at 25° C., may be selected from the group consisting of: 3-hydroxybutan-2-one (Acetyl Methyl Carbinol, CAS No. 513-86-0); 1-hydroxypropan-2-one (ACETOL, CAS No. 116-09-6); N,N-Dimethylacetamide (CAS No. 127-19-5); 3-hydroxypentan-2-one (acetyl ethyl carbinol, CAS No. 3142-66-3); isobutyric acid (Isobutyric acid, ≥99%, FCC, CAS No. 79-31-2); 5-HEXENOL (CAS No. 821-41-0); 4-methylpentan-1-ol (4-METHYL-1-PENTANOL, CAS No. 626-89-1); ethyl 2-hydroxypropanoate (Ethyl Lactate, CAS No. 97-64-3); dimethyl malonate (CAS No. 108-59-8); (E)-hex-3-en-1-ol (3-hexen-1-ol, CAS No. 544-12-7); (E)-hex-3-en-1-ol (trans-3-HEXEN-1-OL, CAS No. 928-97-2); heptan-3-ol (3-Heptanol, ≥98%, CAS No. 589-82-2); 2-mercaptoethan-1-ol (2-HYDROXYETHANETHIOL, CAS No. 60-24-2) furan-2-ylmethanol (FURFURYL ALCOHOL, CAS No. 98-00-0); 2-oxopropanoic acid (PYRUVIC ACID BRI, CAS No. 127-17-3); 1,5diaminopentane (CAS No. 462-94-2); hexan-1-ol (Hexanol, CAS No. 111-27-3); (E)-hex-4-en-1-ol (TRANS-4-HEXENOL, CAS No. 6126-50-7); heptan-2-ol (2-Heptanol, ≥97%, CAS No. 543-49-7); (E)-hex-2-en-1-ol (TRANS-2-HEXENOL, CAS No. 2305-21-7); (Z)-hex-2-en-1-ol (cis-2-HEXEN-1-OL, CAS No. 928-94-9); 1-AMINO-2-PROPANOL (CAS No. 78-96-6); methyl furan-2-carboxylate (METHYL 2-FUROATE, CAS No. 611-13-2); 1-hydroxybutan-2-one (1-HYDROXY-2-BUTANONE, CAS No. 5077-67-8); 3-(methylthio)hexan-1-ol (3-Methylthio)-1-hexanol, ≥97%, CAS No. 51755-66-9); Methyl sulfoxide, ≥99% (CAS No. 67-68-5); 3-mercaptobutan-2-ol (2-Mercapto-3-butanol, mixture of isomers, ≥97%, FG, CAS No. 37887-04-0); 3-methyl-2-oxobutanoic acid

-   -   (dimethyl pyruvic acid, CAS No. 759-05-7);         3-methoxy-3-methylbutan-1-ol (3-Methoxy-3-Methyl-1-Butanol, CAS         No. 56539-66-3); (5-methylfuran-2-yl)methanol (5-methyl furfuryl         alcohol, CAS No. 3857-25-8); 2,4-Dimethyl-2-pentenoic acid (CAS         No. 21016-46-6); 2-methylbutanoic acid (METHYL-2-BUTYRIC ACID         NAT, CAS No. 116-53-0); 2-butoxyethan-1-ol (2-Butoxyethanol, CAS         No. 111-76-2); 4-hydroxy-4-methylpentan-2-one         (4-Hydroxy-4-methyl-2-pentanone, CAS No. 123-42-2); ethyl         2-hydroxy-2-methylbutanoate (ethyl 2-hydroxy-2-methyl butyrate,         CAS No. 77-70-3); 2-(methylthio)ethan-1-ol         (2-(METHYLTHIO)ETHANOL, CAS No. 5271-38-5); 2-oxobutanoic acid         (2-Oxobutyric acid, ≥97%, 600-18-0); 3-METHYLCYCLOHEXANOL (CAS         No. 591-23-1); 2-METHYLCYCLOHEXANOL (CAS No. 583-59-5);         3-(ethylthio)propan-1-ol (3-Ethylthiopropanol, CAS No.         18721-61-4); propyl 2-hydroxypropanoate (PROPYL LACTATE, CAS No.         616-09-1); (E)-hept-4-en-1-ol (cis-4-HEPTEN-1-OL, CAS No.         6191-71-5); thiophene-2-carbaldehyde (2-THIOPHENECARBOXALDEHYDE,         CAS No. 98-03-3); ethyl 3-hydroxybutanoate (Ethyl-3-Hydroxy         Butyrate, CAS No. 5405-41-4); 2-hydroxybenzaldehyde         (Salicylaldehyde, ≥98%, CAS No. 90-02-8);         (tetrahydrofuran-2-yl)methanol (Tetrahydrofurfuryl alcohol,         ≥98%, CAS No. 97-99-4); heptan-1-ol (Heptyl alcohol, ≥97%, FCC,         CAS No. 111-70-6); (2E,4Z)-hexa-2,4-dien-1-ol (2,4-HEXADIEN-1-OL         (SORBIC ALCOHOL), CAS No. 111-28-4); (2E,4Z)-hexa-2,4-dien-1-ol         (trans,trans-2,4-Hexadien-1-ol, ≥97%, CAS No. 17102-64-6);         furan-2(5H)-one (2(5H)-furanone, CAS No. 497-23-4);         2,3-BUTANEDIOL (CAS No. 513-85-9); methyl         2-hydroxy-4-methylpentanoate (methyl 2-hydroxy-4-methyl         valerate, CAS No. 40348-72-9); 2-(ethylthio)ethan-1-ol (ethyl         2-hydroxyethyl sulfide, CAS No. 110-77-0); propane-1,2-diol (1,2         PROPYLENE GLYCOL, CAS No. 57-55-6); propane-1,2-diol (PROPYLENE         GLYCOL, CAS No. 57-55-6); formamide (CAS No. 75-12-7);         2-ethylbutanoic acid (2-Ethylbutyric acid, ≥98%, FCC, CAS No.         88-09-5); 2-methylpentanoic acid (2-METHYL PENANOIC ACID FCC,         CAS No. 97-61-0); 2-methoxyphenol (Guaiacol, natural, ≥98%, FG,         CAS No. 90-05-1); (S)-3-(ethylthio)butan-1-ol (3-(ethyl thio)         butanol, CAS No. 117013-33-9); (S)-3-hydroxyoctan-2-one         (3-hydroxy-2-octanone, CAS No. 37160-77-3);         1-(thiophen-2-yl)ethan-1-one (2-ACETYLTHIOPHENE, CAS No.         88-15-3); 4-(methylthio)butan-1-ol (4-Methylthiobutanol, CAS No.         20582-85-8); 2-(methylthio)phenol (O-(METHYLTHIO)PHENOL, CAS No.         1073-29-6); phenylmethanol (BENZYL ALCOHOL, CAS No. 100-51-6);         3-(methylthio)propan-1-ol (3-(Methylthio)-1-propanol, ≥98%, FG,         CAS No. 505-10-2); butyl 2-hydroxypropanoate (Butyl         (S)-(−)-lactate, ≥97%, CAS No. 34451-19-9); butyl         2-hydroxypropanoate (BUTYL LACTATE, CAS No. 138-22-7);         3-mercapto-3-methylbutan-1-ol (3-MERCAPTO-3-METHYL-1-BUTANOL,         CAS No. 34300-94-2); 3-methylpentanoic acid (3-METHYL PENTANOIC         ACID, CAS No. 105-43-1); butyramide (BUTYRAMIDE, CAS No.         541-35-5); (E)-2-methylpent-3-enoic acid (2-METHYL-3-PENTENOIC         ACID, CAS No. 37674-63-8); 1-phenylethan-1-ol (α-Methylbenzyl         alcohol, ≥99%, FCC, CAS No. 98-85-1); 2,4-dimethylphenol (CAS         No. 105-67-9); 1-(2,4-dimethyl-1,3-dioxolan-2-yl)ethan-1-ol         (acetoin propylene glycol acetal, CAS No. 94089-23-3);         2-mercapto-2-methylpentan-1-ol (Tropicol 0.1% IPM, CAS No.         258823-39-1); 2-(2-methoxyethoxy)ethan-1-ol (METHYL CARBITOL,         CAS No. 111-77-3); octan-1-ol (OCTYL ALCOHOL, CAS No. 111-87-5);         Ethyl (±)-2-hydroxycaproate, ≥97% (CAS No. 52089-55-1);         (E)-pent-2-enoic acid (2-PENTENOIC ACID, CAS No. 13991-37-2);         2-mercaptopropanoic acid (2-Mercaptopropionic acid, ≥95%, CAS         No. 79-42-5); ethyl (2R,3S)-2-hydroxy-3-methyl pentanoate         ((+/−)-ETHYL-2-HYDROXY-3-METHYLVALERATE, CAS No. 24323-38-4);         2-methylpentane-2,4-diol (HEXYLENE GLYCOL, CAS No. 107-41-5);         (S)-4-mercapto-4-methylpentan-2-ol         (4-mercapto-4-methyl-2-pentanol, CAS No. 31539-84-1);         1-(p-tolyl)ethan-1-ol (a,p-DIMETHYLBENZYL ALCOHOL, CAS No.         536-50-5); (E)-hex-3-enoic acid (trans-3-Hexenoic acid, ≥98%,         CAS No. 1577-18-0); (Z)-hex-3-enoic acid (cis-3-HEXENOIC ACID         BRI (NATURAL), CAS No. 1775-43-5); 2-methoxy-4-methylphenol         (2-Methoxy-4-methylphenol, ≥98%, FG, CAS No. 93-51-6);         2-(2-ethoxyethoxy)ethan-1-ol (DIETHYLENE GLYCOL MONO ETHYLETHER,         CAS No. 111-90-0); isopentyl 2-hydroxypropanoate (ISOAMYL         LACTATE, CAS No. 19329-89-6); methyl 2-hydroxybenzoate (METHYL         SALICYLATE USP, CAS No. 119-36-8);         1-(2-methoxypropoxy)propan-2-ol (DIPROPYLENE GLYCOL METHYL         ETHER, CAS No. 34590-94-8); heptanoic acid (heptanoic acid, CAS         No. 111-14-8); DIMETHYL SULFONE (CAS No. 67-71-0);         (Z)-2-methylpent-2-enoic acid (Strawberiff, CAS No. 3142-72-1);         (E)-4-methylpent-2-enoic acid (4-METHYL-2-PENTENOIC ACID, CAS         No. 10321-71-8); 2,4-DIMETHYL-2-PENTENOIC ACID (CAS No.         66634-97-7); 2-(ethoxymethyl)phenol (alpha-ethoxy-ortho-cresol,         CAS No. 20920-83-6); 3-mercaptopropanoic acid         (3-MERCAPTOPROPIONIC ACID, CAS No. 107-96-0); ethyl         2-hydroxybenzoate (ETHYL SALICYLATE, CAS No. 118-61-6);         mercaptoacetic acid (CAS No. 68-11-1); 2-Pyrrolidone (CAS No.         616-45-5); 3-phenylpropan-1-ol (PHENYL PROPYL ALCOHOL, CAS No.         122-97-4); hexyl 2-hydroxypropanoate (HEXYL LACTATE, CAS No.         20279-51-0); 1-(2-aminophenyl)ethan-1-one (2-AMINOACETOPHENONE,         CAS No. 551-93-9); methyl 3-hydroxyhexanoate (Methyl         3-hydroxyhexanoate, ≥97%, FG, CAS No. 21188-58-9);         3-methoxyphenol (3-METHOXYPHENOL, CAS No. 150-19-6);         2-methoxy-4-vinylphenol (2-Methoxy-4-vinylphenol, ≥98%, CAS No.         7786-61-0); 4-ethyl-2-methoxyphenol (4-Ethylguaiacol, ≥98%, FCC,         FG, CAS No. 2785-89-9); 2-(o-tolyl)ethan-1-ol (Peomosa, CAS No.         19819-98-8); 2-(m-tolyl)ethan-1-ol (3-Methylphenethyl alcohol,         CAS No. 1875-89-4); 3-(hydroxymethyl)heptan-2-one         (3-octanon-1-ol, CAS No. 65405-68-7); 2-phenoxyethan-1-ol         (2-PHENOXYETHANOL, CAS No. 122-99-6); lactic acid (CAS No.         50-21-5); 2-allyl-6-methoxyphenol (ortho-eugenol, CAS No.         579-60-2); 5-ethyl-4-hydroxy-2-methylfuran-3(2H)-one         (2-Ethyl-4-hydroxy-5-methyl-3(2H)furanone, 20% in PG, CAS No.         27538-09-6); 2-ethyl-4-hydroxy-5-methylfuran-3(2H)-one         (Homofuranol Pure 100% neat, CAS No. 27538-09-6);         (Z)-oct-5-enoic acid ((Z)-5-octenoic acid, CAS No. 41653-97-8);         4-oxopentanoic acid (Levulinic acid, ≥97%, FG, CAS No.         123-76-2); 4-allyl-2-methoxyphenol (EUGENOL, CAS No. 97-53-0);         3-(methylthio)propanoic acid (3-METHYLTHIOPROPIONIC ACID, CAS         No. 646-01-5); (4-methoxyphenyl)methanol (Anisyl Alcohol, CAS         No. 105-13-5); 3-hydroxypropane-1,2-diyl diacetate (Diacetin,         CAS No. 25395-31-7); 2-methoxy-4-propylphenol (DIHYDRO EUGENOL,         CAS No. 2785-87-7); ethyl 3-hydroxyhexanoate (ETHYL 3-HYDROXY         HEXANOATE, CAS No. 2305-25-1);         1-((1-propoxypropan-2-yl)oxy)propan-2-ol (Dipropylene glycol         n-propyl ether, CAS No. 29911-27-1);         (Z)-2-methoxy-4-(prop-1-en-1-yl)phenol ((E)-Isoeugenol, CAS No.         5932-68-3); (E)-2-methoxy-4-(prop-1-en-1-yl)phenol         (cis-iso-Eugenol, CAS No. 5912-86-7);         (S)-3-(hydroxymethyl)octan-2-one (hydroxymethyl hexyl ethyl         ketone, CAS No. 59191-78-5); 2,2′-oxybis(ethan-1-ol) (DIETHYLENE         GLYCOL, CAS No. 111-46-6); 4-(methylthio)-2-oxobutanoic acid         (4-(methyl thio)-2-oxobutyric acid, CAS No. 583-92-6);         N-Methyldiethanolamine (N-Methyldiethanolamine, CAS No.         105-59-9); (E)-hex-3-en-1-yl 2-hydroxypropanoate (cis-3-HEXENYL         LACTATE, CAS No. 61931-81-5); 2-ethoxy-4-(methoxymethyl)phenol         (Methyl Diantilis®, CAS No. 5595-79-9);         4-(ethoxymethyl)-2-methoxyphenol (VANILLYL ETHYL ETHER, CAS No.         13184-86-6); 2-(4-methylthiazol-5-yl)ethan-1-ol (Sulfurol, CAS         No. 137-00-8); (R)-3-hydroxy-4-phenylbutan-2-one         (3-hydroxy-4-phenyl-2-butanone, CAS No. 5355-63-5);         3-ethyl-2-hydroxycyclopent-2-en-1-one (ETHYL CYCLOPENTENOLONE         PURE, CAS No. 21835-01-8); benzyl 2-hydroxypropanoate (BENZYL         LACTATE, CAS No. 2051-96-9);         5-ethyl-2-hydroxy-3-methylcyclopent-2-en-1-one (5-ethyl-3-methyl         cyclotene, CAS No. 53263-58-4);         3-ethyl-2-hydroxy-4-methylcyclopent-2-en-1-one (3-ethyl-4-methyl         cyclotene, CAS No. 42348-12-9);         2-hydroxy-3,5,5-trimethylcyclohex-2-en-1-one         (2-HYDROXY-3,5,5-TRIMETHYL-2-CYCLOHEXENONE, CAS No. 4883-60-7);         DIPROPYLENE GLYCOL-N-BUTYL ETHER (CAS No. 29911-28-2);         3-(hydroxymethyl)nonan-2-one (3-(HYDROXYMETHYL)-2-NONANONE, CAS         No. 67801-33-6); 3,7-dimethyloctane-1,7-diol (HYDROXYOL, CAS No.         107-74-4); 2-(2-hydroxypropan-2-yl)-5-methylcyclohexan-1-ol         (Geranodyle, CAS No. 42822-86-6); propyl 4-hydroxybenzoate         (PROPYL-p-HYDROXYBENZOATE, CAS No. 94-13-3);         5-(hydroxymethyl)furan-2-carbaldehyde         (5-(Hydroxymethyl)furfural, ≥99%, CAS No. 67-47-0); ethyl         4-hydroxybenzoate (ETHYL-p-HYDROXYBENZOATE, CAS No. 120-47-8);         4-propyl syringol (CAS No. 6766-82-1);         4-allyl-2,6-dimethoxyphenol (4-Allyl-2,6-dimethoxyphenol, ≥90%,         CAS No. 6627-88-9); ETHYL-3-HYDROXY OCTANOATE (CAS No.         7367-90-0); diethyl 2,3-dihydroxysuccinate (Diethyl L-tartrate,         ≥99%, CAS No. 87-91-2); diethyl 2-hydroxysuccinate (DIETHYL         MALATE, CAS No. 626-11-9); triethylene glycol (CAS No.         112-27-6);         (2S,3R)-3-(((2S,3R)-3-mercaptobutan-2-yl)thio)butan-2-ol         (a-METHYL-b-HYDROXYPROPYL-a-METHYL-b-MERCAPTOPROPYL SULFIDE, CAS         No. 54957-02-7); (2-phenyl-1,3-dioxolan-4-yl)methanol         (Benzaldehyde glyceryl acetal, CAS No. 1319-88-6); ethyl         3-hydroxy-3-phenylpropanoate (ETHYL-3-HYDROXY-3-PRENYL         PROPIONATE, CAS No. 5764-85-2);         1-(heptyloxy)-3-hydroxypropan-2-one (Heptanol gylceryl acetal,         CAS No. 72854-42-3); phenethyl 3-hydroxypropanoate (PHENYL ETHYL         LACTATE, CAS No. 10138-63-3);         2-methoxy-4-(4-methyl-1,3-dioxolan-2-yl)phenol (VANILLIN         PROPYLENE GLYCOL ACETAL, 68527-74-2);         3-hydroxy-4,5-dimethylfuran-2(5H)-one (CARAMEL FURANONE (3% IN         TRIACETIN), CAS No. 28664-35-9);         5-ethyl-3-hydroxy-4-methylfuran-2(5H)-one (MAPLE FURANONE         (NEAT), CAS No. 698-10-2);         2-ethoxy-4-(4-methyl-1,3-dioxolan-2-yl)phenol (ETHYL VANILLIN         PROPYLENE GLYCOL ACETAL, CAS No. 68527-76-4);         2-hydroxy-1,2-diphenylethan-1-one (Benzoin, CAS No. 119-53-9);         3-((2-isopropyl-5-methylcyclohexyl)oxy)propane-1,2-diol         (3-1-MENTHOXYPROPANE-1,2-DIOL, CAS No. 87061-04-9);         (R)-2-hydroxy-N-(2-hydroxy ethyl)propanamide (lactoyl         ethanolamine, CAS No. 5422-34-4); 2,3-dihydroxypropyl         5-hydroxydecanoate (glyceryl 5-hydroxydecanoate, CAS No.         26446-31-1); 1-hydroxy-4-methyl-2-pentanone         (1-hydroxy-4-methyl-2-pentanone, CAS No. 68113-55-3);         2-(2-hydroxypropoxy)propan-1-ol (dipropylene glycol, CAS No.         25265-71-8); 2-phenylethan-1-ol (Phenyl Ethyl Alcohol, CAS No.         60-12-8); and combinations thereof.

A solubilizer having a Hansen hydrogen-bonding parameter of greater than 9 MPa^(0.5), a Hansen polarity parameter of greater than 5 MPa^(0.5), and a vapor pressure of less than 267 Pa measured at ° C. may be selected from the group consisting of: phenylmethanol; 2-(2-hydroxypropoxy)propan-1-ol; propane-1,2-diol; 1-((1-propoxypropan-2-yl)oxy)propan-2-ol; 1-(2-methoxypropoxy)propan-2-ol; 4-allyl-2-methoxyphenol; 2-phenylethan-1-ol; and combinations thereof.

Secondary Solubilizer

The fluid composition may contain one or more secondary solubilizers in addition to the solubilizing materials disclosed above, such as a polyol (components comprising more than one hydroxyl functionality), a glycol ether, or a polyether. If the secondary solubilizers present in the fluid composition fall within the Hansen solubility parameters and vapor pressure of the solubilizing materials, the secondary solubilizers should be considered in the total weight percentage of the solubilizing materials in the freshening composition.

Exemplary oxygenated solvents comprising polyols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and/or glycerin. The polyol used in the freshening composition of the present disclosure may be, for example glycerin, ethylene glycol, propylene glycol, dipropylene glycol.

Exemplary oxygenated solvents comprising polyethers are polyethylene glycol, and polypropylene glycol

Exemplary oxygenated solvents comprising glycol ethers are propylene glycol methyl ether, propylene glycol phenyl ether, propylene glycol methyl ether acetate, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, dipropylene glycol n-propyl ether, ethylene glycol phenyl ether, diethylene glycol n-butyl ether, dipropylene glycol n-butyl ether, diethylene glycol mono butyl ether, dipropylene glycol methyl ether, tripropylene glycol methyl ether, tripropylene glycol n-butyl ether, other glycol ethers, or mixtures thereof. The oxygenated solvent may be ethylene glycol, propylene glycol, or mixtures thereof. The glycol used may be dipropylene glycol.

The oxygenated solvent may be added to the composition at a level of from about 0.01 wt. % to about 50 wt. %, by weight of the composition, alternatively from about 0.01 wt. % to about 20 wt. %, by weight of the composition alternatively from about 0.05 wt. % to about 10 wt. %, alternatively from about 0.1 wt. % to about 5 wt. %, by weight of the overall composition.

Water

The fluid composition may comprise water. The fluid composition may comprise water in an amount from about 0.25 wt. % to about 20 wt. % water, alternatively about 0.25 wt. % to about 10 wt. % water, alternatively about 1% to about 5% water, alternatively from about 1% to about 3% water, alternatively from about 1% to about 2% water, by weight of the fluid composition. Without wishing to be bound by theory, it has been found that by formulating the perfume mixture to have a mol-weighted average Clog P of less than about 2.5, water can be incorporated into the fluid composition at a level of about 0.25 wt. % to about 9.5 wt. %, alternatively about 0.25 wt. % to about 7.0 wt. %, by weight of the overall composition.

Malodor Blockers

The fluid composition may include one or more malodor blockers that dull the sensor of smell to a human, while not unduly interfering with the scent of the fluid compositions. Exemplary malodor blockers may be selected from the group consisting of: 1,1,2,3,3-pentamethyl-1,2,3,5,6,7-hexahydro-4H-inden-4-one (Cashmeran, 33704-61-9); 3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-6-yl acetate Flor (acetate/herbaflorate, CAS No. 5413-60-5); 1-((2-(tert-butyl)cyclohexyl)oxy)butan-2-ol (Ambercore, CAS No. 139504-68-0); 2-(8-isopropyl-6-methylbicyclo[2.2.2]oct-5-en-2-yl)-1,3-dioxolane (Glycolierral/Glycoacetal, CAS No. 68901-32-6); (E)-oxacyclohexadec-13-en-2-one (Habanolide, CAS No. 111879-80-2); (Z)-cyclooct-4-en-1-yl methyl carbonate (Violiff, CAS No. 87731-18-8); 7-methyloctyl acetate (Iso Nonyl Acetate, CAS No. 40379-24-6); ethyl dodecanoate (Ethyl laurate, CAS No. 106-33-2); 4,5-epoxy-4,11,11-trimethyl-8-methylenebicyclo(7.2.0)undecane (Caryophyllene Oxide, CAS No. 1139-30-6); 1,3,4,6,7,8alpha-hexahydro-1,1,5,5-tetramethyl-2H-2,4alpha-methanophthalen-8(5H)-one (Isolongifolanone, CAS No. 23787-90-8); dodecan-1-ol (1-dodecanol, CAS No. 112-53-8); 8,8-dimethyl-3a,4,5,6,7,7a-hexahydro-1H-4,7-methanoinden-6-yl propionate (frutene, CAS No. 76842-49-4); (Z)-non-6-en-1-ol (CIS-6-NONEN-1-OL FCC, CAS No. 35854-86-5); dodecanenitrile (CLONAL, CAS No. 2437-25-4); (E)-dec-4-enal (DECENAL (TRANS-4), CAS No. 65405-70-1); (1-methyl-2-((1,2,2-trimethylbicyclo[3.1.0]hexan-3-yl)methyl)cyclopropyl)methanol (JAVANOL, CAS No. 198404-98-7); (E)-1,1-dimethoxy-3,7-dimethylocta-2,6-diene (CITRAL DIMETHYL ACETAL, CAS No. 7549-37-3); 2,6-di-tert-butyl-4-methylphenol (BHT, CAS No. 128-37-0); oxydibenzene, (Diphenyl oxide, CAS No. 101-84-8); (E)-3,7-dimethylocta-2,6-dien-1-yl palmitate (Hexarose, 3681-73-0); 3-methyl-5-phenylpentan-1-ol (Phenyl hexanol, CAS No. 55066-48-3); 3-(3,3-dimethyl-2,3-dihydro-1H-inden-5-yl)propanal (Hivernal, CAS No. 173445-65-3); 3-(1,1-dimethyl-2,3-dihydro-1H-inden-5-yl)propanal (Hivernal, CAS No. 300371-33-9); 2,2,6,6,7,8,8-heptamethyldecahydro-2H-indeno[4,5-b]furan (Amber x-treme, CAS No. 476332-65-7); (R,Z)-1-(2,6,6-trimethylcyclohex-2-en-1-yl)pent-1-en-3-one (Alpha methyl ionone, CAS No. 127-42-4); 3-(6,6-dimethylbicyclo[3.1.1]hept-2-en-2-yl)-2,2-dimethylpropanal (Pinyl isobutyraldehyde alpha, CAS No. 33885-52-8); (E)-3,7-dimethylocta-1,3,6-triene (Cis-ocimene, CAS No. 3338-55-4); 1-(5,5-dimethylcyclohex-1-en-1-yl)pent-4-en-1-one (Neobutenone alpha, CAS No. 56973-85-4); (E)-cyclohexadec-5-en-1-one (5-cylohexadene-1-one, CAS No. 37609-25-9); 2-isopropyl-5-methylphenol (thymol, CAS No. 89-83-8; and combinations thereof.

The fluid composition may comprise up to 2 wt. % of malodor blockers, or from 0.0001 wt. % to 2 wt. % of malodor blockers, based on the total weight of the fluid composition.

Reactive Aldehydes

The fluid composition may include one or more reactive aldehydes that neutralize malodors in vapor and/or liquid phase via chemical reactions. The reactive aldehydes provide a genuine malodor neutralization and function not merely by covering up or masking odors. A genuine malodor neutralization provides a sensory and analytically measurable (e.g. gas chromatograph) malodor reduction.

Reactive aldehydes may react with amine-based odors, following the path of Schiff-base formation. Volatiles aldehydes may also react with sulfur-based odors, forming thiol acetals, hemi thiolacetals, and thiol esters in vapor and/or liquid phase. It may be desirable for these vapor and/or liquid phase reactive aldehydes to have virtually no negative impact on the desired perfume character of a product. Aldehydes that are partially volatile may be considered a reactive aldehyde as used herein.

Suitable reactive aldehydes may have a vapor pressure (VP) in the range of about 0.0001 torr to 100 torr, alternatively about 0.0001 torr to about 10 torr, alternatively about 0.001 torr to about 50 torr, alternatively about 0.001 torr to about 20 torr, alternatively about 0.001 torr to about 0.100 torr, alternatively about 0.001 torr to 0.06 torr, alternatively about 0.001 torr to 0.03 torr, alternatively about 0.005 torr to about 20 torr, alternatively about 0.01 torr to about 20 torr, alternatively about 0.01 torr to about 15 torr, alternatively about 0.01 torr to about 10 torr, alternatively about 0.05 torr to about 10 torr, measured at 25° C.

The reactive aldehydes may also have a certain boiling point (B.P.) and octanol/water partition coefficient (P). The boiling point referred to herein is measured under normal standard pressure of 760 mmHg. The boiling points of many reactive aldehydes, at standard 760 mm Hg are given in, for example, “Perfume and Flavor Chemicals (Aroma Chemicals),” written and published by Steffen Arctander, 1969.

The octanol/water partition coefficient of a reactive aldehyde is the ratio between its equilibrium concentrations in octanol and in water. The partition coefficients of the reactive aldehydes used in the fluid composition may be more conveniently given in the form of their logarithm to the base 10, log P. The log P values of many reactive aldehydes have been reported. See, e.g., the Pomona92 database, available from Daylight Chemical Information Systems, Inc. (Daylight CIS), Irvine, Calif. However, the log P values are most conveniently calculated by the “CLOGP” program, also available from Daylight CIS. This program also lists experimental log P values when they are available in the Pomona92 database. The “calculated log P” (Clog P) is determined by the fragment approach of Hansch and Leo (cf., A. Leo, in Comprehensive Medicinal Chemistry, Vol. 4, C. Hansch, P. G. Sammens, J. B. Taylor and C. A. Ramsden, Eds., p. 295, Pergamon Press, 1990). The fragment approach is based on the chemical structure of each reactive aldehyde, and takes into account the numbers and types of atoms, the atom connectivity, and chemical bonding. The Clog P values, which are the most reliable and widely used estimates for this physicochemical property, are alternatively used instead of the experimental log P values in the selection of reactive aldehydes for the fluid composition.

The Clog P values may be defined by four groups and the reactive aldehydes may be selected from one or more of these groups. The first group comprises reactive aldehydes that have a B.P. of about 250° C. or less and Clog P of about 3 or less. The second group comprises reactive aldehydes that have a B.P. of 250° C. or less and Clog P of 3.0 or more. The third group comprises reactive aldehydes that have a B.P. of 250° C. or more and Clog P of 3.0 or less. The fourth group comprises reactive aldehydes that have a B.P. of 250° C. or more and Clog P of 3.0 or more. The fluid composition may comprise any combination of reactive aldehydes from one or more of the Clog P groups.

The fluid composition of the present disclosure may comprise, by total weight of the fluid composition, from about 0% to about 30% of reactive aldehydes from group 1, alternatively about 25%; and/or about 0% to about 10% of reactive aldehydes from group 2, alternatively about 10%; and/or from about 10% to about 30% of reactive aldehydes from group 3, alternatively about 30%; and/or from about 35% to about 60% of reactive aldehydes from group 4, alternatively about 35%.

Exemplary reactive aldehydes which may be used in a fluid composition of the present disclosure include, but are not limited to, Adoxal (2,6,10-Trimethyl-9-undecenal), Bourgeonal (4-t-butylbenzenepropionaldehyde), Lilestralis 33 (2-methyl-4-t-butylphenyl)propanal), Cinnamic aldehyde, cinnamaldehyde (phenyl propenal, 3-phenyl-2-propenal), Citral, Geranial, Neral (dimethyloctadienal, 3,7-dimethyl-2,6-octadien-1-al), Cyclal C (2,4-dimethyl-3-cyclohexen-1-carbaldehyde), Florhydral (3-(3-Isopropyl-phenyl)-butyraldehyde), Citronellal (3,7-dimethyl 6-octenal), Cymal, cyclamen aldehyde, Cyclosal, Lime aldehyde (Alpha-methyl-p-isopropyl phenyl propyl aldehyde), Methyl Nonyl Acetaldehyde, aldehyde C12 MNA (2-methyl-1-undecanal), Hydroxycitronellal, citronellal hydrate (7-hydroxy-3,7-dimethyl octan-1-al), Helional (alpha-methyl-3,4-(methylenedioxy)-hydrocinnamaldehyde, hydrocinnamaldehyde (3-phenylpropanal, 3-phenylpropionaldehyde), Intreleven aldehyde (undec-10-en-1-al), Ligustral, Trivertal (2,4-dimethyl-3-cyclohexene-1-carboxaldehyde), Jasmorange, satinaldehyde (2-methyl-3-tolylproionaldehyde, 4-dimethylbenzenepropanal), Lyral (4-(4-hydroxy-4-methyl pentyl)-3-cyclohexene-1-carboxaldehyde), Melonal (2,6-Dimethyl-5-Heptenal), Methoxy Melonal (6-methoxy-2,6-dimethylheptanal), methoxycinnamaldehyde (trans-4-methoxycinnamaldehyde), Myrac aldehyde isohexenyl cyclohexenyl-carboxaldehyde, trifernal ((3-methyl-4-phenyl propanal, 3-phenyl butanal), lilial, P.T. Bucinal, lysmeral, benzenepropanal (4-tert-butyl-alpha-methyl-hydrocinnamaldehyde), Dupical, tricyclodecylidenebutanal (4-Tricyclo5210-2,6decylidene-8butanal), Melafleur (1,2,3,4,5,6,7,8-octahydro-8,8-dimethyl-2-naphthaldehyde), Methyl Octyl Acetaldehyde, aldehyde C-11 MOA (2-methyl deca-1-al), Onicidal (2,6,10-trimethyl-5,9-undecadien-1-al), Citronellyl oxyacetaldehyde, Muguet aldehyde 50 (3,7-dimethyl-6-octenyl) oxyacetaldehyde), phenylacetaldehyde, Mefranal (3-methyl-5-phenyl pentanal), Triplal, Vertocitral dimethyl tetrahydrobenzene aldehyde (2,4-dimethyl-3-cyclohexene-1-carboxaldehyde), 2-phenylproprionaldehyde, Hydrotropaldehyde, Canthoxal, anisylpropanal 4-methoxy-alpha-methyl benzenepropanal (2-anisylidene propanal), Cylcemone A (1,2,3,4,5,6,7,8-octahydro-8,8-dimethyl-2-naphthaldehyde), Precylcemone B (1-cyclohexene-1-carboxaldehyde); Pinyl isobutyraldehyde alpha (3-(6,6-dimethylbicyclo[3.1.1]hept-2-en-2-yl)-2,2-dimethylpropanal; and Hivernal (3-(3,3-dimethyl-2,3-dihydro-1H-inden-5-yl)propanal/3-(1,1-dimethyl-2,3-dihydro-1H-inden-5-yl)propanal).

Still other exemplary reactive aldehydes include, but are not limited to, acetaldehyde (ethanal), pentanal, valeraldehyde, amylaldehyde, Scentenal (octahydro-5-methoxy-4,7-Methano-1H-indene-2-carboxaldehyde), propionaldehyde (propanal), Cyclocitral, beta-cyclocitral, (2,6,6-trimethyl-1-cyclohexene-1-acetaldehyde), Iso Cyclocitral (2,4,6-trimethyl-3-cyclohexene-1-carboxaldehyde), isobutyraldehyde, butyraldehyde, isovaleraldehyde (3-methyl butyraldehyde), methylbutyraldehyde (2-methyl butyraldehyde, 2-methyl butanal), Dihydrocitronellal (3,7-dimethyl octan-1-al), 2-Ethylbutyraldehyde, 3-Methyl-2-butenal, 2-Methylpentanal, 2-Methyl Valeraldehyde, Hexenal (2-hexenal, trans-2-hexenal), Heptanal, Octanal, Nonanal, Decanal, Lauric aldehyde, Tridecanal, 2-Dodecanal, Methylthiobutanal, Glutaraldehyde, Pentanedial, Glutaric aldehyde, Heptenal, cis or trans-Heptenal, Undecenal (2-, 10-), 2,4-octadienal, Nonenal (2-, 6-), Decenal (2-, 4-), 2,4-hexadienal, 2,4-Decadienal, 2,6-Nonadienal, Octenal, 2,6-dimethyl 5-heptenal, 2-isopropyl-5-methyl-2-hexenal, Trifernal, beta methyl Benzenepropanal, 2,6,6-Trimethyl-1-cyclohexene-1-acetaldehyde, phenyl Butenal (2-phenyl 2-butenal), 2-Methyl-3(p-isopropylphenyl)-propionaldehyde, 3-(p-isopropylphenyl)-propionaldehyde, p-Tolylacetaldehyde (4-methylphenylacetaldehyde), Anisaldehyde (p-methoxybenzene aldehyde), Benzaldehyde, Vernaldehyde (1-Methyl-4-(4-methylpentyl)-3-cyclohexenecarbaldehyde), Heliotropin (piperonal) 3,4-Methylene dioxy benzaldehyde, alpha-Amylcinnamic aldehyde, 2-pentyl-3-phenylpropenoic aldehyde, Vanillin (4-methoxy 3-hydroxy benzaldehyde), Ethyl vanillin (3-ethoxy 4-hydroxybenzaldehyde), Hexyl Cinnamic aldehyde, Jasmonal H (alpha-n-hexylcinnamaldehyde), Floralozone, (para-ethyl-alpha,alpha-dimethyl Hydrocinnamaldehyde), Acalea (p-methyl-alpha-pentylcinnamaldehyde), methylcinnamaldehyde, alpha-Methylcinnamaldehyde (2-methyl 3-pheny propenal), alpha-hexylcinnamaldehyde (2-hexyl 3-phenyl propenal), Salicylaldehyde (2-hydroxy benzaldehyde), 4-ethyl benzaldehyde, Cuminaldehyde (4-isopropyl benzaldehyde), Ethoxybenzaldehyde, 2,4-dimethylbenzaldehyde, Veratraldehyde (3,4-dimethoxybenzaldehyde), Syringaldehyde (3,5-dimethoxy 4-hydroxybenzaldehyde), Catechaldehyde (3,4-dihydroxybenzaldehyde), Safranal (2,6,6-trimethyl-1,3-diene methanal), Myrtenal (pin-2-ene-1-carbaldehyde), Perillaldehyde L-4(1-methylethenyl)-1-cyclohexene-1-carboxaldehyde), 2,4-Dimethyl-3-cyclohexene carboxaldehyde, 2-Methyl-2-pentenal, 2-methylpentenal, pyruvaldehyde, formyl Tricyclodecan, Mandarin aldehyde, Cyclemax, Pino acetaldehyde, Corps Iris, Maceal, and Corps 4322.

The reactive aldehydes may be present in an amount up to 100%, by weight of the fluid composition, alternatively from 1% to about 100%, alternatively from about 2% to about 100%, alternatively from about 3% to about 100%, alternatively about 50% to about 100%, alternatively about 70% to about 100%, alternatively about 80% to about 100%, alternatively from about 1% to about 20%, alternatively from about 1% to about 10%, alternatively from about 1% to about 5%, alternatively from about 1% to about 3%, alternatively from about 2% to about 20%, alternatively from about 3% to about 20%, alternatively from about 4% to about 20%, alternatively from about 5% to about 20%, by weight of the composition.

The fluid composition of the present disclosure may include an effective amount of an acid catalyst to neutralize sulfur-based malodors. It has been found that certain mild acids have an impact on aldehyde reactivity with thiols in the liquid and vapor phase. It has been found that the reaction between thiol and aldehyde is a catalytic reaction that follows the mechanism of hemiacetal and acetal formation path. When the present fluid composition contains an acid catalyst and contacts a sulfur-based malodor, the reactive aldehyde reacts with thiol. This reaction may form a thiol acetal compound, thus, neutralizing the sulfur-based odor. Without an acid catalyst, only hemi-thiol acetal is formed.

Suitable acid catalysts have a VP, as reported by Scifinder, in the range of about 0.001 torr to about 38 torr, measured at 25° C., alternatively about 0.001 torr to about 14 torr, alternatively from about 0.001 to about 1, alternatively from about 0.001 to about 0.020, alternatively about 0.005 to about 0.020, alternatively about 0.010 to about 0.020.

The acid catalyst may be a weak acid. A weak acid is characterized by an acid dissociation constant, K_(a), which is an equilibrium constant for the dissociation of a weak acid; the pKa being equal to minus the decimal logarithm of K_(a). The acid catalyst may have a pKa from about 4.0 to about 6.0, alternatively from about 4.3 and 5.7, alternatively from about 4.5 to about 5, alternatively from about 4.7 to about 4.9. Suitable acid catalyst include those listed in Table 3.

TABLE 3 VP (torr) @ Acid Catalyst 25° C. Formic Acid 36.5 Acetic Acid 13.9 Trimethyl Acetic Acid 0.907 Phenol (alkaline in liquid apps 0.610 yet acidic in vapor phase) Tiglic acid 0.152 Caprylic acid 0.0222 5-Methyl thiophene carboxylic 0.019 acid Succinic acid 0.0165 Benzoic acid 0.014 Mesitylenic acid 0.00211

Depending on the desired use of the fluid composition, one may consider the scent character or the effect on the scent of the fluid composition when selecting an acid catalyst. It may be desirable to select an acid catalyst that provides a neutral to pleasant scent. Such acid catalysts may have a VP of about 0.001 torr to about 0.020 torr, measured at 25° C., alternatively about 0.005 torr to about 0.020 torr, alternatively about 0.010 torr to about 0.020 torr. Non-limiting examples of such acid catalyst include 5-methyl thiophene carboxaldehyde with carboxylic acid impurity, succinic acid, or benzoic acid.

The composition may include about 0.05% to about 5%, alternatively about 0.1% to about 1.0%, alternatively about 0.1% to about 0.5%, alternatively about 0.1% to about 0.4%, alternatively about 0.4% to about 1.5%, alternatively about 0.4% of an acid catalyst by weight of the fluid composition.

When an acid catalyst is present with a reactive aldehyde, the acid catalyst may increase the efficacy of the reactive aldehyde on malodors in comparison to the malodor efficacy of the reactive aldehyde on its own. For example, 1% reactive aldehyde and 1.5% benzoic acid provides malodor removal benefit equal to or better than 5% reactive aldehyde alone.

Method of Atomizing a Fluid Composition

A method of atomizing a fluid composition may include energizing the fluid composition with a thermal actuator and atomizing the heated composition from a nozzle. Energizing the fluid composition may be accomplished with a micro-thermal or micro-mechanical actuation on a microfluidic die.

The method of atomizing the fluid composition may include atomizing the fluid composition in a direction that is from 0 degrees to 90 degrees from the direction of action of gravity.

The microfluidic delivery device and method of delivering a freshening composition may be used to deliver a fluid composition into the air. The microfluidic delivery device may also be used to deliver a fluid composition into the air for ultimate deposition on one or more surfaces in a space. Exemplary surfaces include hard surfaces such as counters, appliances, floors, and the like. Exemplary surfaces also include carpets, furniture, clothing, bedding, linens, curtains, and the like. The microfluidic delivery device may be used in homes, offices, businesses, open spaces, cars, temporary spaces, and the like. The microfluidic delivery device may be used with freshening compositions, malodor removal compositions, insect repellant compositions, and combinations thereof.

Thermally-activated microfluidic dies may produce a primary droplet as well as one or more secondary, or satellite, droplets. The presence, number, and size of primary and secondary droplets may depend on fluid properties such as surface tension and rheology, fluid thermodynamics such as critical pressure, microfluidic die geometry, and firing parameters such as firing frequency.

Fluid Composition Droplet Distribution

It may be desirable for the microfluidic dispensing device to atomize a distribution of small and large droplets of the fluid composition. Smaller droplets will remain in the air longer, allowing the droplets to fill a space and even travel to other adjacent spaces. Larger droplets will settle onto nearby surfaces, resulting in evaporation of the larger droplets from the nearby surfaces, providing longevity of the fluid composition atomization near the device. Further, consumers may desire a consistent experience that results from a consistent distribution of droplets atomized from the microfluidic device in order to experience a consistent release of fluid composition. In the case of a fluid composition comprising a perfume mixture, a consistent distribution of droplets of a perfume mixture may result in a consistent level of scent noticeability both close to the device and at adjacent spaces. If the droplet distribution changed over time, resulting in a change in the number of larger droplets that fall near the device and a number of smaller droplets that travel away from the device, the noticeability near and far from the device would change over time.

A consumer desirable droplet distribution may include 80% or greater of the total volume of the plurality of droplets is less than 10 picoliters (“pL”) and 50% or greater, 60% or greater, 70% or greater, of the total volume of the plurality of droplets is less than 5 pL.

A consumer desirable droplet distribution may include a bimodal distribution having 80% or greater of the total volume of the plurality of droplets is less than 10 pL; 30% or greater of the total volume of the plurality of droplets is less than 5 pL; and 30% or greater of the total volume of the plurality of droplets is from 6 pL to 10 pL.

Video-Based Droplet Sizing Method

The determination of size and velocity of droplets ejected from a microfluidic die is often done through video methods. One commonly used technique is the use of video to capture images of droplets in silhouette in front of a light source. The light source is configured to emit a very short pulse of light (on the order of 1 μs) which is coordinated in time to occur with a known delay after firing the nozzle. Despite the fact that the droplets are moving, the short duration of the light pulse makes the droplets appear to be stationary in the video frame, where the droplet size can be estimated from the size of the silhouette in pixels. The camera is placed so that the droplets are in the focal plane of the camera so that the silhouette is an accurate representation of the droplet outlines. The droplets are imaged immediately after exiting the nozzles to minimize the reduction of velocity due to aerodynamic drag and change of size due to evaporative losses. The image frame extends from approximately 0.5 mm from the nozzle plate of the microfluidic die to approximately 2 mm from the nozzle plate.

A commercially available instrument using this technique is the JETXPERT™ instrument manufactured by ImageXpert Inc. of Nashua, N.H. This instrument can be configured to capture individual video frames, and the associated software may size one or more of the droplets in each frame. To enable more automated analysis of a large number of frames, the JETXPERT™ instrument may be configured to store video frames for later analysis. In this way, a statistically significant number of droplets may be analyzed, sufficient for constructing a histogram. While the number of droplets required to reconstruct a distribution function depends partly upon the nature of the distribution, generally a sample size of 500 droplets or more is sufficient. A similar instrument may be constructed from commercially available components including a digital camera with a digitally gated shutter feature, a suitable light source as described above, and a delay timer or function generator for coordinating the firing of the droplets of fluid composition from the microfluidic die with the pulsing of the light source and camera shutter.

Post processing a series of video frames may be done with any of several commercially available software packages for mathematical analysis (for example, MATLAB® from The MathWorks Inc., Mathematica from Wolfram Research, or ImageJ from the US National Institutes of Health) or through custom software. Regardless of the underlying computing platform, the sizing procedure consists of binarizing the pixels of the image using a grayscale threshold determined from a thresholding algorithm such as the maximum entropy method described by Kapur, et al. (J. N. Kapur, P. K. Sahoo, and A. K. C. Wong, A new method for gray-level picture thresholding using the entropy of the histogram, Comput. Vision Graphics Image Process. 29, 1985, 273-285). Thereafter, the resulting pixel clusters may be filtered by size or shape to eliminate non-drop artifacts or overlapping droplets, and the resulting clusters may have their diameter or volume inferred from the number of pixels in the silhouette. In this way, statistics on a large number of droplets may be collected. Assuming that the silhouette is circular and that the corresponding droplet is spherical, the diameter may be calculated from

$d = \frac{2\mspace{14mu} \delta \mspace{14mu} \sqrt{n}}{\sqrt{\pi}}$

where d is the diameter of the droplet, δ is the length of one side of a (square) pixel in the video frame, and n is the number of pixels in the silhouette. The value δ may be determined using the method described below. Using the same assumptions, the volume of the droplet may be calculated

$v = \frac{4\mspace{14mu} \delta^{3}\mspace{14mu} n^{3\text{/}2}}{3\mspace{14mu} \sqrt{\pi}}$

from where v is the volume of the droplet, and other the symbols have the same meaning as above.

The method may be calibrated using a reticle with shapes of known sizes. One example is the model FA079 distortion target reticle available from Max Levy Autograph of Philadelphia, Pa. This reticle provides an array of 62.5 μm dots that, when placed in the focal plane of the imaging device, can be used to calibrate the drop sizing method.

Examples

TABLE 4 Perfume Mixture Weight % of Perfume CAS No. Material Mixture 928-96-1 Beta Gamma Hexenol 4.760 121-32-4 Ethyl Vanillin 4.760 140-11-4 Benzyl Acetate 4.760 3681-71-8 Cis 3 Hexenyl Acetate 4.760 39255-32-8 Ethyl 2 Methyl Pentanoate 4.760 488-10-8 Cis Jasmone 4.760 24851-98-7 Methyl Dihydro Jasmonate 4.760 18479-58-8 Dihydro Myrcenol 4.760 106-72-9 Melonal 4.800 78-70-6 Linalool 4.760 151-05-3 Dimethyl Benzyl Carbinyl 4.760 Acetate 105-95-3 Ethylene Brassylate 4.760 14901-07-6 Ionone Beta 4.760 61792-11-8 Lemonile 4.760 115-95-7 Linalyl Acetate 4.760 81782-77-6 Undecavertol 4.760 300371-33-9 Neo Hivemal 4.760 22471-55-2 Thesaron 4.760 3738-00-9 Cetalox 4.760 141773-73-1 Helvetolide 4.760 Orange Terpenes 4.760

TABLE 5 Example Fluid Composition Level Component (wt. %) Perfume Mixture of Table 4 90 Propylene Glycol (CAS No. 57-55-6) 10

An exemplary microfluidic die capable of producing the drop size distributions described above was used. The microfluidic die includes heaters with a rectangular shape having length (in the flow direction) of 54 μm and width of 50 μm. The corresponding microfluidic chamber in the flow feature layer has the same dimensions as the heater, additionally with height 12 μm. The nozzle plate layer has thickness 12 μm, and the nozzle orifice has diameter 23 μm. The heater impedance is approximately 50Ω, and the delivered energy to the heater is approximately 4 μJ over a an approximately 2000 ns period. The die has 32 thermal actuators, which can be fired individually.

The following description presents drop size distribution data using the Example Fluid Composition of Table 5. The example Fluid Composition was placed in a cartridge comprising the above described microfluidic die. An electrical fixture was used to fire the cartridge. The electrical fixture is capable of firing the nozzles at a user selectable frequency and firing energy. It is also capable of controlling the substrate heating feature of the microfluidic die to maintain a user selectable temperature. Further, it is capable of firing a user selectable subset of the array of nozzles. During collection of the drop size data, the microfluidic die substrate was maintained at 30° C. and the firing energy was maintained at approximately 8% over the minimum required energy to fire a droplet. The minimum required firing energy was determined by the fixture using an algorithm that estimates the onset of jetting from the thermal response of the microfluidic die.

FIG. 9 shows a histogram of observed droplets using the described Video-Based Droplet Sizing Method. The observations were made of Example Fluid Composition shown in Table 5 above with the microfluidic die firing at 1000 Hz. The histogram represents droplets observed in approximately 90 video frames. The distribution of droplet volumes is bimodal, reflecting the fact that the described microfluidic die produces a primary drop and some number of secondary droplets. In the histogram, a vertical line divides the two modes at the 5 pL volume. The relative liquid volume contained in the two modes is indicated by the quantities labeled “volume split”. In the sample reported in FIG. 9, approximately 68.4% of liquid volume is delivered in droplets having 5 pL or greater volume, and 31.6% is delivered in droplets having less than 5 pL.

FIG. 10 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 9. Also shown in this plot is the value of D_(v,0.5), 8.91 pL, the theoretical droplet volume which divides the dispensed volume, with half of the dispensed volume in droplets having less than the indicated droplet volume and half in droplets having greater than the indicated volume.

FIG. 11 shows a histogram of droplets produced by the same microfluidic die and the Example Fluid Composition, now firing at 2000 Hz. FIG. 12 Histogram of cumulative distribution function of volume for the observations of FIG. 11.

FIG. 13 shows a histogram of droplets produced by the same microfluidic die and the Example Fluid Composition, now firing at 3000 Hz. FIG. 14 Histogram of cumulative distribution function of volume for the observations of FIG. 13.

FIG. 15 shows a histogram of droplets produced by the same microfluidic die and the Example Fluid Composition, now firing at 4000 Hz. The histogram shows that at this higher frequency, the relative number of small droplets is higher, and thus the volume delivered in droplets having less than 5 pL volume is substantially greater, at approximately 61.6%, as compared to firing frequencies of 1000 Hz, 2000 Hz, and 3000 Hz.

FIG. 16 is a histogram showing the cumulative distribution function of the droplet volume for the observations in FIG. 15. The value of Dv,0.5 is 3.03 pL, reflecting the fact that the dispensed volume from the microfluidic die firing at 4000 Hz has a substantially higher content of small droplets.

FIG. 17 shows a histogram of droplets produced by the same microfluidic die and the Example Fluid Composition, now firing at 5000 Hz. FIG. 18 Histogram of cumulative distribution function of volume for the observations of FIG. 17.

FIG. 19 shows a histogram of droplets produced by the same microfluidic die and the Example Fluid Composition, now firing at 6000 Hz. FIG. 20 Histogram of cumulative distribution function of volume for the observations of FIG. 19.

FIG. 21 is a plot of volume fraction of drops dispensed in droplets having volume 5 pL or less, versus firing frequency. FIG. 21 shows a summary of the volume fraction data presented in the preceding histograms. As the frequency increases, the fraction of volume emitted in small droplets increases until about 4000 Hz. After 4000 Hz, the microfluidic die enters a “bistable” operating regime, where it alternately ejects a large drop and a few secondary drops, or only a spray of very small drops. As a result, the intermittently ejected large drops influences the relative fraction of volume contained in small drops. Using this combination of microfluidic die and fluid composition, the optimal firing frequency for generating drops which travel far from the dispenser is approximately 4000 Hz.

Without wishing to be bound by theory, it is believed that the bistable operation occurs when the microfluidic die is operated above its characteristic refill frequency. This is the frequency at which the microfluidic die has the minimum required time to refill completely. The refill time may be determined, for example, by observing the movement of the meniscus in the nozzle orifice. Using a strobe light source that has a precise time delay in relation to the electrical firing of the microfluidic die, it is possible to observe when the meniscus in the nozzle orifice returns to its rest position after firing. The period required for the liquid meniscus to return to its rest position may be regarded as the period corresponding to the characteristic firing refill frequency.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

It should be understood that every maximum numerical limitation given throughout this specification will include every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention. 

What is claimed is:
 1. A method of atomizing a fluid composition, the method comprising the steps of: providing a fluid composition; atomizing the fluid composition from a nozzle of a microfluidic die, wherein the atomized fluid composition comprises a plurality of droplets having a bimodal distribution, wherein the bimodal distribution comprises: 80% or greater of the total volume of the plurality of droplets is less than 10 pL; 30% or greater of the total volume of the plurality of droplets is less than 5 pL; and 30% or greater of the total volume of the plurality of droplets is from 6 pL to 10 pL.
 2. The method of claim 1, wherein the plurality of droplets comprise: 80% or greater of the total volume of the plurality of droplets is from 1 to 10 pL; and 50% or greater of the total volume of the plurality of droplets is from 1 to 5 pL.
 3. The method of claim 1, wherein the step of atomizing the fluid composition further comprises atomizing the fluid composition at a frequency of 1000 Hz to 6000 Hz.
 4. The method of claim 3, wherein the step of atomizing the fluid composition further comprises atomizing the fluid composition at a frequency of 2000 Hz to 4000 Hz.
 5. The method of claim 1, wherein the fluid composition comprises at least 60 wt. % of a perfume mixture, based on the total weight of the fluid composition.
 6. The method of claim 1 further comprising the step of heating the composition with a thermal actuator.
 7. The method of claim 6, wherein the step of atomizing the fluid composition further comprises atomizing the heated fluid composition from a nozzle of a microfluidic die, the microfluidic die comprising a silicon semiconductor substrate containing a plurality of heater resistors, at least one fluid chamber associated with each heater resistor, and at least one nozzle associated with each fluid chamber.
 8. The method of claim 6, wherein the step of atomizing the fluid composition further comprises atomizing the heated fluid composition from a nozzle in a direction that is from 0 degrees to 90 degrees from the direction of action of gravity.
 9. The method of claim 6, wherein the microfluidic die comprises a nozzle plate comprising the at least one nozzle, and wherein the nozzle plate comprises an oleophobic surface coating.
 10. The method of claim 1, wherein the fluid composition comprises a perfume mixture. 